214 



BIOLOGY OF THE LABORATORY MOUSE 



blood, as monocytes, and to all other forms as histiocytes. Tumors of 

 monocytes or histiocytes will be named histiocytomata (monocytoma) and 

 the systemic disease characterized by these cells histiocytoma tosis (mono- 

 cytomatosis). Monocytic leukemia is a synonymous term for leukemic 



Table i 



Tumors and Tumor-like Conditions or Blood Forming and Blood 



Destroying Tissues in Mice 



* No cases on record in mice. 



histiocytomatosis (monocytomatosis)." In consideration of the above we 

 have employed the classification shown in Table i. 



Each of these types of tumors may or may not show an abnormal blood 

 picture. When these tumors are accompanied by a marked increase of the 

 tumor cells in the circulating blood, outside of the lymphatic system, this 

 condition is called leukemia. The absence or paucity of these tumor cells in 

 the circulating blood of animals that have developed tumors of this group is 



